Polycarbonate has good mechanical properties such as tensile strength, impact resistance, etc. and also has good dimension stability, heat resistance, optical transparency, etc. Thus, it has many industrial applications. However, although polycarbonate has good impact resistance at room temperature, its impact resistance rapidly becomes worse at low temperature. To improve such a disadvantage, various copolymers have been researched and it has been known that polysiloxane-polycarbonate copolymer has good impact resistance at low temperature.
Although the polysiloxane-polycarbonate copolymers produced by conventional methods have good impact resistance at low temperature, they are vulnerable to heat deformation at high temperature, and the transparency becomes lower. Thus, there is a limitation in the use of such copolymers as an optical material. In addition, they have poor resistance to scratch and abrasion, and thus when used as an exterior material, they show poor quality. In order to improve the resistance to abrasion, mixing of polysiloxane-polycarbonate copolymer with another polymer was tried, but such a mixing resulted in deterioration of other properties such as transparency, etc.